136 M. Walpers on the Irregular Form 



have stood^ two minute scales, which appear to be the rudi- 

 ments of the petals. 



The flower of the Leguminosce acquires a laterally com- 

 pressed appearance from the abortion of the four superior 

 ovaries ; and I am not aware of a single case where the flower 

 of any one of this family corresponds exactly to the scheme 

 properly deducible for it. 



The petals forming the carina are, as is well known, those 

 standing nearest to the ovarium ; and they must therefore, in 

 the true papilionaceous flower, be those situated innermost ; 

 and indeed they always closely surround the ovarium and 

 proceed perfectly parallel with it. The two following petals, 

 or the wings, retain their original position, and place them- 

 selves, in consequence of the lateral compression of the entire 

 flower, over the carinal leaves, with which, by the too great 

 pressure and considerable development of the former (as in 

 several Phaseole<B and many Trifoliem) they frequently cohere 

 at their base, naturally however above the unguis. But they 

 are generally prevented by the gamosepalous calyx from de- 

 veloping and spreading themselves freely as they would 

 otherwise do. The last petal, the vexillum, opposed to the 

 ovarium at its upper suture, stands both from its situation as 

 well as position, — as may be distinctly seen in numerous 

 Sophoreae, — furthest from the ovarium, consequently meets 

 with the fewest hindrances to its independent development, 

 and thus frequently attains to a considerable size in pro- 

 portion to the other petals : this also depends on the stronger 

 nutriment, which in consequence of its distance from the ova- 

 rium appears to be conveyed to it through the calyx. Thus 

 then in the bud at least the vexillum will be folded round the 

 other petals and inclose them, whence arises the well-known 

 vexilla-covering aestivation {mstivatio vexillaris) of the Papi- 

 lionacecs. 



If the petals are very narrow, and the catycinal tube very 

 long and narrow, they at times cohere through their whole 

 length at their margins to a tube whose border exhibits five in- 

 cisions which open according to the type of the papiliona- 

 ceous flower, as in many TrifoliecB, 



